Solar garden lights I don't think are bright enough for an anchor light. Great in addition though.

These however wrapped around a 1" PVC pipe and run up the mast are extremely bright. We were one of the brightest anchor lights at Fitzroy Is over Easter. Enough light to get around on deck, at 9.5m up. I can lower it and lash it to the front of the mast as a steaming light as well. 1 is plenty and will wrap about 3 times around the tube. I used a length of old high quality speaker wire tied off in the tube, so that if anything gets tangled up it has enough strength to give it a strong yank. I used butyl tape in addition to the double sided tape supplied.
I have a wired mast light and use it but because we drop the mast , the mast plug > deck plug regularly fail even at the highest IP rating with self amalgamating tape. Seems to be 2yr maximum lifespan. I have recently taken to putting the plug assembly through the cabin top and siliconeing around the wire so the plug is out of the weather and when we drop the mast just pulling the "wire and silicon plug" out then reseal it.